hyperv/stor: Fix the INQUIRY checks

Don't check the area that the host has not filled.

PR: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=209443
PR: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=210425
Submitted by: Hongjiang Zhang <honzhan microsoft com>
Reviewed by: sephe, Dexuan Cui <decui microsoft com>
MFC after: 3 days
Sponsored by: Microsoft OSTC
Differential Revision: https://reviews.freebsd.org/D6955